Originally Posted by sherbert

Sorry people, should have given a description and trigger warning for the article. Anyway, here's the important part:
"Although it is quite common for pets to travel in the cabin of US aircraft, particularly on internal flights, it’s not something that happens much in Europe. The Civil Aviation Authority (CAA) told The Independent: “Under European regulations EU airlines are allowed to carry pets of up to 8kg in the aircraft cabin, however, it is up to the discretion of each individual airline as to whether they do indeed allow it.“ As far as we are aware no UK operator allows pets to travel in the cabin (other than assistance dogs). Instead, some UK airlines carry pets in the hold for a fee. Dogs, cats or ferrets being flown into the UK require a pet passport and must be microchipped and vaccinated against rabies.

Neither Ryanair nor easyJet take pets in the hold, and only allow assistance animals on board. BA transports pets in the hold via its sister company IAG Cargo; it has a “last on, first off” policy for animals, meaning the minimum of noise and disruption, and features an online tracking tool for nervous owners. Fees and required pet-carrier size depend on the animal, so passengers are advised to get in contact with the airline prior to the flight."

As far as I know, no carrier will allow you to fly into the UK with a pet as baggage: they MUST fly in as cargo. You might want to look into flying into Paris, renting a car and taking the train or a ferry into the UK. While you would still likely not be able to fly your pet in the cabin, you'd at least be able to fly him in as baggage which will save you several thousand $$$.